Gitignore failed_uuids.txt, restore AND semantics for --only labels

- Add /tests/failed_uuids.txt to .gitignore so local test failures
  don't pollute git status
- Detect whether --only tokens are UUIDs (8-char hex) or trace labels:
  UUIDs use OR (any match), labels use AND (all must match). This
  preserves the documented behavior of --only 2D Bubbles while
  supporting the CI retry path --only UUID1 UUID2.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

.gitignore

@@ -34,6 +34,7 @@ docs/documentation/parameters.md
 /tests/*/**
 !/tests/*/golden.txt
 !/tests/*/golden-metadata.txt
+/tests/failed_uuids.txt
 
 # NVIDIA Nsight Compute
 *.nsys-rep

toolchain/mfc/test/test.py

@@ -42,7 +42,7 @@
 class TestTimeoutError(MFCException):
     pass
 
-# pylint: disable=too-many-branches, trailing-whitespace
+# pylint: disable=too-many-branches, too-many-locals, too-many-statements, trailing-whitespace
 def __filter(cases_) -> typing.List[TestCase]:
     cases = cases_[:]
     selected_cases = []
@@ -66,12 +66,19 @@ def __filter(cases_) -> typing.List[TestCase]:
         raise MFCException("Testing: Your specified range [--from,--to] is incorrect. Please ensure both IDs exist and are in the correct order.")
 
     if len(ARG("only")) > 0:
+        # UUIDs are 8-char hex (CRC32): use OR so --only UUID1 UUID2 selects
+        # any matching test. Labels use AND so --only 2D Bubbles selects both.
+        _uuid_mode = all(len(t) == 8 and t.isalnum() and not t.isalpha() for t in ARG("only"))
         for case in cases[:]:
             case: TestCase
 
             checkCase = case.trace.split(" -> ")
             checkCase.append(case.get_uuid())
-            if not set(ARG("only")).intersection(set(checkCase)):
+            if _uuid_mode:
+                if not set(ARG("only")).intersection(set(checkCase)):
+                    cases.remove(case)
+                    skipped_cases.append(case)
+            elif not set(ARG("only")).issubset(set(checkCase)):
                 cases.remove(case)
                 skipped_cases.append(case)